Pneumatic pulley for motion-picture films



May 17 1927.

v. c. DE YBARRoND'o PNEUMATIC. PULLEY FQR MOTION PICTRE FILMS l Filed June 30. 192'6 Patented May 17, 1927.

UNITED STATES.

`vrNoENT c. neYBAnnoNno, or Los ANGELES, CALIFORNIA.

IPNEUMATIC PULLEY FOR MOTION-IPIGTURE FILMS.

Application led June 30, 1926. Serial No. 119,525.

My invention relates to pulleysand more particularly to a pneumatic pulley.

In preparing motion picture film commercially the negative must be developed, fixed, washed and dried. A positive is then printed from the negative and the positive must be developed, fixed, washed Vand dried.

Variousmachines have been devised for passing the film through these preparing processes. After the positive lm is prepared it must be run through a projecting machine to produce a moving'picture. The picture produced may be greatly mared by any scratches upon a' surface of the negative film, which are transmitted to the positive in printing, or by scratches made upon a surface of the positive. filnrdirectly. Y1t hasbeen found that pulleysover which the film. Aust pass in the preparing and projecting m" Ychines cause such scratches upon the film.

It is a broad objectof provide a pulley for use in handling motion picture film which will not scratch the surface of the film.

The pulley of my invention is designed to be used either asa drive pulley or as an idle pulley. Openings are provided in the film contacting surface of the pulley from which air may be drawn through the axle of the pulley. When the film lies over 'the mouth of these openings a vacuum is thus created inthe openings which holds the film a ainst the pulley and prevents any slipping of the film relative thereto.

It is therefore another object of my invention to provide a pneumatic pulley which utilizes a vacuum to draw a film into nonslipping relation with said pulley." Y If it is desired to pass the film idly over the pulley, air is blown outwardly from the axle through the aforementioned openings' thus creating a cushioning layer of air betwecn the pulley. and the film.

Astill further -object of my invention is to provide a pneumatic pulley in which an air cushion is formed between the pulley and a moving picture film passing'over it vso that the surface of the film does not contact the pulley.

Yet another objectof my invention is to provide a pneumatic pulley in which a vacuum formed to grip a moving' picture film thereto is broken when it is desired that said film be disengaged by said pulley.

,peripheral surface 13 and an axlalvbearing my invention to Further objects and advantages will be made evident hereinafter. l

Fig.1is a side elevational view of a preferred embodiment of my invention.

Fig. 2 is a vertical sectional view taken lmedially. and longitudinally through the pulley of my invention.

Fig. 3 is a vertical sectional view taken Fig. 4 is a fragmentary vertical sectional 65 viewof a modified form of my invention. A. pneumatic pulley 10 has a pulley wheel 11 which is shown as provided w1th end fianges 12. rI`he Wheel 11 has a cylindrical 70 opening .14. Connecting the opening 14 with the surface 13 are radial openings 15.

-A neck 16 projects from one end ofthe pulley wheel 11V and threadedly receives a driv ing pulley 17 which is adapted to receive a belt (not shown) for the purpose of imparting a rotary ymovement to the pulley wheel 11.

An axle 20 fits neatly within the bearing opening 14 of the pulley wheel 11 so that the latter may rotate readily thereon. A central passageway 21 isv formed throughout the length of the axle 20, one end of the passageway 21being closed by a plug 22 threadedly received therein.' The plug 22 has a knurled head 23 for a purpose which will be described later. The axle 2() has ports 28 formed therein so that as the pulley wheel 11 is rotated upon the axle 20 the radial openings 15 will come into registry with the ports 28 over a certain'angular portion of the rotation of the pulley wheel 11. Chan-- nels 30 are formed in the outer surface of the `axle 20 as shown in Figs. 3 and 4, for a purposeI which will be described later.

A support 35 has an opening 36 in which an end of the axle 2O is adapted to be snugly received. A thumb screw 38 is threadedly receive in a suitable aperture'formed in the support 35 and'is adapted to be screwed 100 down against the axle 20 to retain the same in a. given position in the opening 36. passage 40 is formed in the support 35 which communicates with a nipple 41 threadedly received at 42 in the lower end of the sup- 1.05 port 35 and which is connected by a union 43 to a pressure or exhaust line 44. The pressure or exhaust line 44 is connected to the pressure or exhaust end of a suitable fiuid pump (not shown). The support 35 110 is connected to`the exhaust end of passage sof Cil

may be secured in any manner so as to hold the pulley wheel. 11 in a suitable position for use. n

In Fig. 4 a pulley wheel 50 is shown which is identical to the pulley wheel 11 excepting that an outer cylindrical surface 52 thereof is provided with sprocket teeth 53. These sprocket teeth 53 are spaced at equal angles radially around the surface 52 so as to penetrate the holes provided at the edges of a strip of film which is passed over the surface 52 of the pulley wheel 50.

The operation of my invention is as fol-- lows:

/ When it is desired'to use the pulley wheel 11 as a drive pulley, means, such as a belt' laced upon the drivingI pulley 17, are used or rotating the pulley wheel 11.- A motion picture film 60, as shown by dotted lines in Fig. 3, is now passed around the pulley Wheel 11, as shown. The pipe 44 pump and a vacuum is drawn upon the 21 of the axle 20. The outer mouths of those of the radial openings 15 which are now in communication with the ports 28 are closed by contact of the film 60 with the outer surface 13 of the pulley wheel 11. The vacuum in the passageway 2l isv thereore communicated through the ports 28 to this group of the radial openings 15. The vacuum inv this group of radial openings 15 draws the film 60 closely against the outer surface of the pulley' wheel 11 and, as the latter rotates, causes the film to (be moved with the surface 13 and prevents any sliding action of the film 60 relative to the surface 13. As the Wheel 11 rotates the group of openings 15 upon which a vacuum has been drawn registry with the ports 28 so that they no longer communicate through the'ports 28 with the passage 21,.

As the openings 15 are thus shut off from communication with the passa eway 21 they come into communication witg channels 30 which communicate with a lower radial opening 15, the mouth of which is open so that 'air is admitted through such lower openingto relieve the vacuum in each opening 15 as it moves into communication with a channel 30. As the vacuum is thus relieved in the openings 15 they release their grip upon the film 60 Whichcontinues in its prescribed path away from the pulley ,wheel 11. It will be noted that the channels 30 are formed in the outer surface of the axle 20 adjacent to each of the oppositeends of the ports 28. Thus the pulley wheel 11 may be rotated in either direction and the vacuum formed in the radial openings 15 will be relieved as just described.

In case it is 60 to and from the y ulley wheel 11 at a different angle than t at shown in Fig. 3,

a fluid pass successively out of.

desired to extend the film 38 may be released from contact with the axle 2O and the'axle 20 may be rotated by manually engaging the knurled head 23 so that orts 28 will be disposed opposite the area of) the peripheral surface 13 which will be contacted by the film 60. The thumb screw reset to secure the axle 20 in this position. The pulley will now operate in exactly the same manner described excepting that the gripping area will be, disposed at a different position about the axis of the pulley.

When it is desired to use the pulley wheel 1l as an idle pulley the pi e 44 is connected to the exhaust end of a uid um and a fluid, preferably air, is pumpedpunclr pressure intotlie passage 2l of the axle 20. This air under pressure escapes'through the ports 28 and is conducted through the radial openings 15 to the eriphcral surface 13. The film 60 is here p aced about the pulley wheel 11 in the same manner as-is shown in Fi 3 but passes over the pulle wheel 11 without coming in contact with tierpcripheral surface 13. This is due to the escaping of air from the openings 15 so as to form an air cushion between the ,film 60 and the eripheral surface 13. This protects the film 60 from any chance of being scratched by contact with the pulley Wheel 11.

In Fig. 4 the pulley wheel 50 is provided with sprocket teeth 53 which are adapted to engage with the holes usually provided along the edges of a motion picture film, otherwise the Wheel 50 is similar in construction to the pulley wheel 11 and either the vacuum gripping action or the air cushion action may set up between the pulley 50 and the film 60. The teeth 53, however, provide a means for engaging the film so that the pulley 50 may be used as a drive pulley and since the vacuum gripping action will thus be unnecessary, an air cushion may be set u between the film 60 and the surface 52 ofj the pulley wheel 50 for the purpose of preventing any scratching of the surface of the film 60 by contact with the surface 52 of the pulley 50.

It is contemplated to make special use of the pneumatic pulley 10 in the drier of a motion picture film developin machine. Here warm air is passed outwardly through the pulley wheel 11, this air not onl causing the film 60 to ride easily over t e pulley but acting upon the film as a drying agent. Moreover. when it is desired to treat the film when drying with any chemical, this chemical in the form of a vapor may be dissolved in the air passed outwardly through the pulley wheel 11 and thus be brought against the fihn by the streams of air issuing from the radial openings 15.

claim as my invention:

1. In combination: a pulle the thumb screw wheel having a peripheral surface in w ich openings 38 may then be.

are formed; means for formingay'acuum.

in one of said openings when its mouth is covered; and means for connecting an uncovered openin with said covered op'ening for releasing said vacuum before said mouth is uncovered. l

2. In combination: a pulley wheel having a peri heral surface in which openings are forme an axle upon which said wheel may turn; there being a passagein said axle; means for extracting the air from said passageway to form a vacuum in one of said openings when its lnouth is covered; and means for releasing said vacuum before said mouth is uncovered.

3. In combination: a. pulley wheel having a peripheral Isurface in which'openings are formed :1a-n axle upon which said wheel may turn, there being a passage `in said axle and a port connecting: said passage with one of said openings when said opening is disosed within a 'certain range of its` possible radial positions; andimeans for imposing a vacuum upon said passage which will be communicated through said port to said. opening when the outer mouth of Said opening is closed. I

4. In combination: a. pulley wheel having a peripheral surface in which openings are formed; and means for forcing a 'luid from said openings to form a iuid cushion between said wheel and a flexible member guided in direction by said wheel.

In combination: a'pulley wheel having a peri heral surface in which openings are forme( an axle upon Which said Wheel may turn, there beingA a passage in said axle and a port connecting said passage with one of said openings when said opening is disposed within a certain range of its possible radial positions; means for supporting said riphery axle; means for rotatably adjusting said axle; and means for imposing a vacuum upon said passage which will be communicated through said port to s'aid opening when the outer mouth of said opening is closed. 6. In combination: an axle having a passage formed in the interior thereof and a port connecting said passage with the bearing surface ofsaid axle; a pulley wheel adapted to be. rotatably supported upon said axle, and having openings connecting the bearing surface of said pulley with the periphery thereof; and means for extracting the air from said passageway to form a vaeuum in said openings when these are in reg istry with said port and when the outer mouths thereof are closed, there being means for breaking said vacuum in said covered openings by connecting these with uncovered openings.

7. In combination: an axle havinga passage formed in thel interior thereof and a port connecting said passage with the bearing sui-face of said axle; a pulley wheel adapted to be rotatably supported upon said axle. and having openings connecting the bearing surface of said pulley with the pethereof; and means for extracting the air from said passageway to form a vacuum in said openings when these are in registry with said port and-when the outer mouths thereof are closed, there being a port formed in the bearing surface of said axle for lbreaking said vacuum in said covered openings by connecting these with uncovered openings.

In testimony7 whereof, I have hereunto set my hand at Iios Angeles, California, this 24th day of June, 1926.

VINCENT C. DE YBARRONDO. 

